I was thinking about making my own minimalist TTL CPU for fun and knowledge, when this question came to mind. Basically, if a 1-Bit Computer can only recognize 2 numbers, 0 and 1, doesn't that mean that the computer could only have 2 registers or instructions? Then, I found the Motorola MC14500B, which is a 1-bit computer that has 16 instructions, with 4 pins for opcodes. Is the MC14500B considered a "true" 1-bit computer, since it has more than 2 instructions, and if so, could I apply the same concept to internel registers where there are more than just 2, but the actual logic going on in the CPU and the memory works on 1-bit? This is a simple question that I need some clarification on, so thank you for your help!
Electronic – Can A 1-Bit Computer have more than 2 Registers
cputtl
Best Answer
Many 8-bit CPU architectures have instructions that consist of more than one byte. I see no reason why a 1-bit CPU could not similarly have some instructions that consist of multiple bits.
At a more general level: The "bit-ness" of a CPU typically only reflects the size of its registers. It's perfectly possible (and, indeed, quite common) for instructions, the address bus, and/or even the data bus to be different widths from registers.